Thisdevelopment is still in its infancy but has much promise. In collaboration with P. Haydon Ph.D. of Iowa State, members of the BRC have done preliminary trials on the combination of near-field spectroscopy with the ion probes. The near field system comprises a single 1005m optical fiber pulled to a diameter of 50nm. The fiber is coupled to an excitation laser light, which can stimulate intracellular reporting molecules such as the calcium sensitive dye Fluo-3, and calcium green. The fiber is carefully maneuvered into the cellular near field and the emission signal collected. In this way the operator can image the ion activity immediately below the plasma-membrane with the added advantages that the whole cell is not illuminated and bleached dye is replaced by diffusion. In combining the ion-selective calcium probes with intracellular reporting molecules a problem has been knowing the activity of calcium immediately under the point of probe approach. However, the Seris probes are brought into the cellular near field, precisely in the location one would like to place the optical fiber. As this fiber is small, and the ion sensor in the electrode a liquid it was reasoned that we could place the near field microscope inside the ion-selective electrode. Our first attempts were surprisingly successful, with dual imaging achieved on the first attempt. We could clearly image the immediate, sub-membrane, micro-domain when the electrode was in the near pole position and simultaneously collect a differential voltage and flux value. We are now in the process of planning further collaborations to streamline the system being developed and make the electrode construction more robust and simpler. Biological collaborations will then follow to examine how cells modulate their different transport option such as flux versus sequestration to stimuli both natural and pharmacological. We intend to start this work with astrocytes and neurons.